Insecticides generally refer to a wide range of environmental interventions that have as their objective, the reduction of insect pests to an acceptable level from a particular area. Specific control techniques include chemical, physical and biological mechanisms, however, this invention is directed towards chemical insecticides.
The great majority of insecticides used today comprise synthetic compounds that affect the nervous system of insects on contact. Historically, chlorinated hydrocarbons such as DDT, chlordane and toxaphene had been used, but many of these compounds have been banned in the U.S. or fallen out of favor. Organophosphates, such as malathion, parathion, and dimethoate are currently widely used active ingredients for insecticides. A wide range of biological insecticides are also in use today. Although insecticides are widely used and provide great benefits to the users, environmental and social costs of widespread use can be high. For example, the use of DDT has been banned in the U.S. since 1973 because of its long-range environmental and human safety impacts, despite the fact that it functioned well as an insecticide.
A variety of insecticide formulations are known. For example, U.S. Pat. No. 6,159,956 discusses the preparation and use of difluorovinylsilane as an insecticide. Likewise, U.S. Pat. No. 6,162,799 discusses the preparation and use of certain naphthoquinone derivatives as pesticides and U.S. Pat. No. 6,124,466 promotes the use of certain nitroisourea derivatives for their insecticidal activity.
In formulating insecticides, a variety of considerations need to be weighed. First, obviously, one must utilize an active ingredient, or ingredients, that possess the appropriate degree of insecticidal activity towards the group of insects it is intended to be used against. However, the active ingredient must be such that it is safe for human use and reasonably environmentally safe, when being applied according to its instructions. One means of ensuring that the active ingredient is safe for human use is to use an active ingredient(s) that has a recognized tolerance for use on food, thus allowing for use in food preparation areas. Preferably, the active ingredient(s) is susceptible to being naturally degraded by organisms in the soil, or otherwise, upon extended exposure to the environment.
Typically, the active ingredient(s) in an insecticide formulation are solublized or dispersed in a carrier, which will generally make up the bulk of the formulation. A variety of carrier characteristics, such as solubility or dispersability of the active ingredient in the carrier, toxicity of the carrier, odor, volatile organic content, biodegradability, and flammability, need to be considered in the choice of an effective carrier. Preferably the active ingredient(s) will be dissolved by, or dispersed in, the carrier during storage so that no mixing is required just prior to use. Carrier choice can also be limited by the need to aerosolize or foam the insecticide. Frequently there are trade-offs among these characteristics in choosing the most effective overall carrier.
Most preferably, the carrier(s) can dissolve the active ingredient(s) into an insecticide formulation that achieves the appropriate level of insecticidal activity, while at the same time posing little or no danger to human health and the environment when used as intended. The formulation should also possess low odor, have low volatile organic content, be biodegradable and relatively non-flammable.
It is also desired that the active ingredient in the insecticide composition is non-repellant to termites. By “non-repellant” what is meant is that the termites do not detect the active ingredient and will readily move through the treated zone, picking up a lethal dose of the active ingredient.